A rotating structure, such as a gas turbine engine associated with an aircraft, may include a fan having a plurality of fan blades. When the aircraft is in flight, the fan rotates at high speeds. The fan blades are well-balanced both statically and dynamically so that the fan is not a source of significant dynamic loads. In some situations, however, a bird, a piece of debris, or another object may strike the fan or another part of the engine during operation, thereby causing a fan blade or at least a portion thereof to break-off from the fan. Such a blade-out event can cause the fan to become unbalanced and thus a source of significant vibration. This vibration is undesirably transmitted to the engine mount and airframe of the aircraft. One way to reduce or eliminate the vibration is to stop the rotation of the damaged engine. If the rotation of the fan is stopped, however, the engine exerts significant drag on the aircraft, which not only decreases airspeed and thereby increases the time required to get the aircraft safely to ground, but also complicates the process of flying the aircraft.